Asphalt is one of the world's oldest engineering materials, having been used since the beginning of civilization. Asphalt is a strong, versatile and chemical-resistant binding material that adapts itself to a variety of uses. For example, asphalt is used to bind crushed stone and gravel into firm tough surfaces for roads, streets, and airport runways. Asphalt, also known as pitch, can be obtained from either natural deposits, or as a by-product of the petroleum industry. Natural asphalts were extensively used until the early 1900s. The discovery of refining asphalt from crude petroleum and the increasing popularity of the automobile served to greatly expand the asphalt industry. Modern petroleum asphalt has the same durable qualities as naturally occurring asphalt, with the added advantage of being refined to a uniform condition substantially free of organic and mineral impurities.
The raw material used in modern asphalt manufacturing is petroleum, which is naturally occurring liquid bitumen. Asphalt is a natural constituent of petroleum, and there are crude oils that are almost entirely asphalt. The crude petroleum is separated into its various fractions through a distillation process. After separation, these fractions are further refined into other products such as asphalt, paraffin, gasoline, naphtha, lubricating oil, kerosene and diesel oil. Since asphalt is the base or heavy constituent of crude petroleum, it does not evaporate or boil off during the distillation process. Asphalt is essentially the heavy residue of the oil refining process.
Some potential sources of asphalt are the heavy crude oils that can be generated from oil sands. A common process flow for separating the non-petroleum particulate matter from the oil in oil sands can start with an extraction process, such as a cold water or hot water extraction. This generates a bitumen “froth” that can be physical separated from most of the extraction water. The “froth” can then be further treated to remove additional water and small particles in the froth phase by treating the froth with a non-polar solvent. This results in a separate oil phase and water plus particles phase. The water plus particles phase can be referred to as “tailings”. Currently, tailings from an oil sands extraction process represent a waste product that is disposed of at a cost, as opposed to being a valuable product that can be incorporated into a product for sale.